1. Field of the Invention
The invention relates chiefly to a controlled valve (defined herein as a valve that operates under a control applied to it) with the possibility of autonomous opening, and an aircraft comprising a controlled valve of this type.
2. Description of the Prior Art
There are prior art controlled valves which, under command or actuation, make it possible to let through a desired flow rate of a fluid between, for example, two chambers within which there are different pressures prevailing. The prior art type controlled valves enable the regulation of flow rates or pressures. To enable stable regulation, the controlled valves are designed to work in a determined range of flow rates. Thus, it is not possible, upon command, for example in the event of trouble, to get the pressures balanced by fast and complete opening of the controlled valve. Furthermore, the prior art type controlled valves act only upon external actuation. Thus, the malfunctioning of the external actuating device makes the controlled valve completely ineffective.
Thus, in the case of the most common uses, there are no safety means available to balance the pressures. In advanced technologies, such as, for example, in aeronautics, clack valves (defined herein as valves that open and shut automatically under pressure applied to them) are used: these clack valves are designed to open if the difference in pressure between their two faces goes beyond a predetermined threshold.
However, it turns out that the fact of having a clack valve or a controlled valve on a partition between, for example, two chambers or between one chamber and the outside, raises major problems. Firstly, there should be the space needed for the controlled valve and the clack valve. This is not always the case, notably if the controlled valves and clack valves have to be placed, for example, on a piping system connecting the tubes of chemical reactors or points of, for example, a petroleum distillation tower.
Furthermore, the fact of making an opening needed for the controlled valve and the clack valve to pass through embrittles the wall. This embrittlement could be partially compensated for by a structure which is, for example, metallic, positioned around the controlled valve and the clack valve. However this metallic structure is costly and heavy. The additional weight has particularly serious implications in the case of aircraft manufacturing.
The French patent application No. FR-A-88 05068, not published on the filing date of the present application, describes a controlled valve capable of opening autonomously under the effect of a pressure difference that exceeds a predetermined threshold.
FIG. 8 of the above mentioned patent application describes a valve with two thrust recovery flaps comprising a telescopic connecting rod that enables the mechanical uncoupling of two flaps and, hence, the autonomous opening of one of the flaps under the effect of a pressure difference that exceeds a threshold.
An object of the present invention is an improvement in a valve with two thrust recovery flaps and autonomous opening, if the pressure difference exceeds a threshold.
In the preferred embodiment of the valve according to the present invention, the rod providing for the coupling of the two flaps is rigid. However, at least one of the flaps can rotate on its axis, to open automatically if the difference in pressures, for example in a predetermined direction, exceeds a threshold.
The joining, during normal operation, of the two flaps, is provided, for example, by the weight of the flap and/or by a spring.
The replacement of the telescopic connection rod by a rigid connection rod makes it possible to improve operating safety and reduce wear and tear.